ALFAGTV6.COM

[dan668s]

Hi,

I've read all kinds of FAQ's and this GTV6 forum without finding a truly similar problem, hopefully some of you could help.

Here are my symptoms:
1. Starts easily
2. Runs fine when cold
3. When temp reaches about 40-45degrees (Celcius) it starts to sputter, starting to fire on 3-5 sylinders and black smoke coming out of the exhaust.
4. Then it just dies, and I can clearly smell fuel. It won't start until plugs are cleaned or waiting to start for about 2-3hours
5. When engine is "hot" (40-45degrees) I can hear a "hissing" sound coming from the front of the plenum when ignition is ON.
It seems like the sound is coming from around the area where the small vacumhose is connected to the plenum at the front right side of the engine.
6. The hissing-sound continues if I disconnent the blue Bosch-connector at the back of the plenum (Cold-start "valve?)

After the engine dies the plugs are black and sooty.

If I leave the ignition on for about 10seconds on warm engine to hear the "hissing" sound, the plugs becomes very wet....

Can my AMF be faulty telling the injectors to constantly spraying fuel, or can it be the water temp sensor not working, telling the system to spray extra fuel on startup (but never stop spraying)??

Does anyone have a clue to what causes this?

[Murray]

Sounds as though you could have a couple of problems:

1) You state that:

If I leave the ignition on for about 10seconds on warm engine to hear the "hissing" sound, the plugs becomes very wet....

Do you mean that with the engine NOT running you hear the hiss and the plugs get wet ? .The fuel pump should not be running with the engine off/ignition on.If you are hearing the "hissing" sound then you're pump is running and the contact inside the AFM is not functioning properly.The hissing sound is normal by the way,it is the sound of fuel being sent through the fuel pressure regulator back to the tank - normal when the engine is running.
However it is not normal that the plugs are getting wet as the injectors should not be open so you may have an injector leakdown problem.


2) As for the generally rich operation at warmer operating temperatures it sounds as though you need to verify the Thermal Time Switch and cold start injector circuit.Have you had a look at Greg's site ? He explains in detail how to check these components for correct operation.


http://www.hiperformancestore.com/L-jetronic.htm

[dan668s]

Sounds as though you could have a couple of problems:

1) You state that:

If I leave the ignition on for about 10seconds on warm engine to hear the "hissing" sound, the plugs becomes very wet....

Do you mean that with the engine NOT running you hear the hiss and the plugs get wet ? .The fuel pump should not be running with the engine off/ignition on.If you are hearing the "hissing" sound then you're pump is running and the contact inside the AFM is not functioning properly.The hissing sound is normal by the way,it is the sound of fuel being sent through the fuel pressure regulator back to the tank - normal when the engine is running.
However it is not normal that the plugs are getting wet as the injectors should not be open so you may have an injector leakdown problem.


2) As for the generally rich operation at warmer operating temperatures it sounds as though you need to verify the Thermal Time Switch and cold start injector circuit.Have you had a look at Greg's site ? He explains in detail how to check these components for correct operation.


http://www.hiperformancestore.com/L-jetronic.htm

Thanks Murray.

Yes the hissing-sound continues with the ignition ON and engine NOT running, so I guess the switch in my AFM is bad then. I have another AFM which have been tampered with (opened up and adjusted), which doesn't give this hissing-sound with ignition ON (engine not running).

I've tried to measure the TTS and cold start injector circuit. I looks OK at cold engine, but my engine doesn't run long enough to verify/read the numbers for the CTS on a hot engine.

Where can I buy a new CTS? www.international-auto.com only lists the TTS (I think).

[Murray]

dan668s yes try replacing the AFM to deal with the fuel pump circuit problem.It could also be the source of your overall "rich" problem as the AFM variable resistor circuit tells the ECU how much fuel to deliver.
Next thing you can try before buying new sensors is get the engine started and then disconnect the "blue" connector to the CSI to see if the excessive fuel condition originates with the cold start circuit.Keep in mind that even if the cold start electrical circuit is OK the CSI can be stuck open mechanically which will deliver excessive fuel to the intake.
Another thing you should check is your fuel pressure (approx 36 psi.).If the fuel pressure regulator or the return line to the tank is blocked you could be getting excessive pressure in the line to the injectors.While you're at it have a look at the throttle position switch to make sure it's not sending an incorrect signal to the ECU. Greg's write-up covers this in detail.
The following website has some great information on numbers for Bosch parts and their equals but IAP should certainly have the CTS.

http://milano75.dammfine.com/

[dan668s]

Problem solved

Kinda embarrasing really, but the cause of this was actually that my mechanic had put the connectors to the CTS and TTS on the wrong sensors. (CTS-connector on the TTS and vica versa...)

I started to suspect this when I pulled what I thought was the plugg to the TTS and the car stopped, and Greg Gordons guide says that the car won't run without the CTS connected. I just switched these two plugs, and now the car runs like a dream again.

Thanks to Murray for your input, and thanks to Greg for the L-Jet tune-up guide

[Murray]

Glad you were able to track it down Might be a good idea to change your oil as you may have dumped a bit of fuel into it while going through this.Final step is to find a good road and give her a good "Italian tuneup" .